[CentOS-docs] Use preformatted blocks in Broadcom wiki page

[Timothy Lee]

  Dear all,

On the Broadcom wiki page, I've moved the formatted codes from tables 
into preformatted blocks.  This makes the raw wiki code easier to read, 
and is consistent with other wiki pages that I've come across during 
translation.

Should the maintainers of that page find such a change undesirable, 
please feel free to revert.

Regards,
Timothy Lee